Solve for $x$ and $y$ using substitution. ${-6x+3y = -3}$ ${y = -3x+9}$
Explanation: Since $y$ has already been solved for, substitute $-3x+9$ for $y$ in the first equation. ${-6x + 3}{(-3x+9)}{= -3}$ Simplify and solve for $x$ $-6x-9x + 27 = -3$ $-15x+27 = -3$ $-15x+27{-27} = -3{-27}$ $-15x = -30$ $\dfrac{-15x}{{-15}} = \dfrac{-30}{{-15}}$ ${x = 2}$ Now that you know ${x = 2}$ , plug it back into $\thinspace {y = -3x+9}\thinspace$ to find $y$ ${y = -3}{(2)}{ + 9}$ $y = -6 + 9$ $y = 3$ You can also plug ${x = 2}$ into $\thinspace {-6x+3y = -3}\thinspace$ and get the same answer for $y$ : ${-6}{(2)}{ + 3y = -3}$ ${y = 3}$